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B Dupont

Publications and source records attributed to B Dupont.

At least 163 records · Page 9Linked to original sources
PubMed1994

Molecular typing of Cryptococcus neoformans serotype D clinical isolates.

Cryptococcus neoformans serotype A is responsible for the majority of cryptococcal infections in AIDS patients. In France, approximately 17% of the patients are infected with serotype D, regardless of their human immunodeficiency virus status. In a retrospective study of 273 patients, we found that serotype D was unevenly distributed in France. We wondered if this was related to the yeast's genetic background. We used karyotyping and DNA fingerprints generated by UT-4p to analyze 40 serotype D clinical isolates. We found an extensive polymorphism, with only two conserved karyotypes from drug-addicted patients living in the same area. Although highly variable, the DNA fingerprints were classified into 10 groups. Four pairs of isolates were identical; three of these pairs were from patients living in the same area, but there was no other correlation with the geographical area. The two isolates with identical karyotypes belonged to the same fingerprint group. Five of the six isolates that made up fingerprint group I were recovered from drug-addicted patients (P < 0.002; chi-square), and all five isolates found in fingerprint group III were from male homosexual patients (P < 0.02). Finally, five of the seven isolates from patients with cryptococcal pneumonia were classified as fingerprint group V (P < 0.04). These results suggest that there are possible relationships between characteristics of the isolates and body localization or even risk factors. Results of the present study warrant other studies on isolates of all serotypes and on isolates from clinical and environmental sources.

Cryptococcus neoformans↗
PubMed1994

[Curative treatment of invasive aspergillosis].

Invasive aspergillosis is an opportunist infection in immunosuppressed hosts among the most difficult to diagnose and to treat. A wide variety of clinical forms exist which may not require the same treatment for each of them. Intravenous amphotericin B and itraconazole are the only available antifungal agents. Amphotericin B is often considered as the gold standard treatment despite its high toxicity particularly with high dosage (1-1.5 mg/kg/day) and its poor results namely in bone marrow transplant recipients. Lipidic amphotericin B is less toxic allowing administration of higher dose however relevant data are limited. Itraconazole is an excellent anti Aspergillus antifungal with low toxicity, however there is a wide intersubject variation in intestinal absorption. It may represent a valuable alternative to amphotericin B in case of intolerance or as a relay treatment and possibly in some cases as a first choice treatment. More studies are necessary particularly in granulopenic patients. Comparative study are urgently needed between both drugs and with new molecules to indicate the best treatment according to the clinical form. The use of hematopoietic growth factors and surgery may improve the outcome.

Amphotericin B↗
PubMed1993

Invasive aspergillosis in patients with acquired immunodeficiency syndrome: report of 33 cases. French Cooperative Study Group on Aspergillosis in AIDS.

PURPOSE: Acquired immunodeficiency syndrome (AIDS)-associated invasive aspergillosis (IA) is a rare condition, which is mainly reported as isolated cases either antemortem or at autopsy. The role of AIDS itself is controversial, because many of the reported patients exhibited the classic risk factors such as neutropenia and steroid therapy. The aims of this study were to report 33 patients with IA during AIDS and their outcome, focusing on the risk factors and the value of diagnostic procedures. PATIENTS AND METHODS: Thirty-three patients from 17 different medical centers in France were retrospectively included in the study. For pulmonary IA, we defined two types of patients: those with "confirmed IA," describing all the patients with histologically proven disease, and those with "probable IA," who had the development of a new pulmonary infiltrate on chest radiograph and a positive bronchoalveolar lavage (BAL) fluid culture for Aspergillus species without identification of other pathogens. For extrapulmonary IA, the diagnostic criteria included both positive histology and culture. RESULTS: Of the 33 cases included in this series, 91% were recorded during the last 3 years (1989 to 1991), suggesting that aspergillosis is an emerging complication in AIDS. Approximately 50% of the patients did not exhibit any classic risk factor, i.e., neutropenia and steroid treatment; almost all patients had a CD4 cell count less than 50/mm3. The mycologic culture from BAL was the method of choice for the diagnosis of invasive pulmonary disease because it was known to correlate well with histologic findings obtained either antemortem or postmortem. Of 28 patients with a positive BAL culture for Aspergillus, 15 underwent a biopsy or autopsy and 14 were positive at histology. Serum antigen detection was positive in only 4 of 16 tested patients. Clinical and radiologic signs did not differ from those observed in neutropenic patients without human immunodeficiency virus, except for the higher incidence of neurologic complications in AIDS. Interestingly, we observed three cases of invasive necrotizing tracheobronchial aspergillosis with acute dyspnea and wheezing. The use of amphotericin B (0.5 mg/kg/d) and/or itraconazole (200 to 600 mg/d) was most often unsuccessful. Only four patients experienced clinical and radiologic improvement. The mean interval between the diagnosis of IA and death was 8 weeks (range: 3 days to 13 months). CONCLUSIONS: This study suggests that aspergillosis is an important life-threatening condition in the advanced stage of AIDS. It requires an early diagnosis with BAL fluid culture and careful therapeutic evaluation.

AIDS-Related Opportunistic Infections↗
PubMed1993

Infection due to Klebsiella rhinoscleromatis in two patients infected with human immunodeficiency virus.

Two cases of rhinoscleroma in patients infected with the human immunodeficiency virus (HIV) who had stayed in an area of endemic Klebsiella rhinoscleromatis are reported. One of the patients presented with oropharyngeal lesions, an unusual clinical picture. Both patients suffered from a major cellular immune deficiency. The importance of Klebsiella rhinoscleromatis infection in AIDS-related oropharyngeal pathology and the possible treatment of such infection in HIV-positive patients are not yet clearly established.

AIDS-Related Opportunistic Infections↗
PubMed1993

The MLC assay as a test for HLA-D region compatibility between patients and unrelated donors: results of a national marrow donor program involving multiple centers.

Mixed lymphocyte culture (MLC) assays from 763 patients and prospective unrelated marrow transplant donors identified through the National Marrow Donor Program (NMDP) were analyzed for their overall utility in measuring HLA-D region compatibility. The assays were performed at 31 different transplant centers (range, 1 to 197; median, 9 assays per center). A total of 325/763 (42.6%) of the tests were judged to be uninterpretable, either due to lack of sufficient control cells included in the assay (89 tests) or to insufficient reactivity by patient and/or donor cells (236 tests). Among the 438 tests that could be interpreted, HLA-Dw phenotyping with HLA-D homozygous cells was performed for a subset of 190. The relative response (RR) values from these 190 tests, however, were not clearly separable into distinct populations; i.e., RR values corresponding to Dw identity versus nonidentity between patient and donor could not be reliably discriminated. The predictive value of a nonreactive MLC for Dw identity was calculated to be 0.91 for RRs of < or = 20%, while the predictive value of a reactive MLC for Dw nonidentity was 0.35 for RRs of > 20%. These results, based on an analysis of data submitted from multiple transplant centers testing patients who had a variety of hematologic disorders, suggest that the MLC assay is a relatively imprecise method for determining HLA-D region compatibility between patient and prospective unrelated marrow donor.

Bone Marrow Transplantation↗
PubMed1993

Candida albicans genotyping in studies with patients with AIDS developing resistance to fluconazole.

We characterized Candida albicans strains responsible for recurrent oropharyngeal candidosis (OPC) in four patients with AIDS who developed clinical and mycological resistance to fluconazole (FCZ). Karyotype and restriction fragment length polymorphism analyses were performed on the clonal populations to differentiate relapse from reinfection, and the results were assessed with those of serotype and FCZ MICs. Despite the polymorphism in chromosomal bands larger than 2.2 Mbp related to an intraclonal variation, karyotype analysis showed a single strain type attributable to each patient. On the other hand, EcoRI and HinfI restriction fragments revealed a polymorphism for one patient between the first sample and the subsequent ones, relevant to the acquisition of a new strain causing the following episodes of OPC. This result coincided with switching of the serotype and with the acquisition of a resistance to FCZ. For the other three patients, the similarity of the DNA electrophoretic patterns and the serotype of the samples suggested that recurrence can be due to the initial strain that generates FCZ resistance. Although useful for epidemiological studies, molecular typing methods seem to be inadequate to detect the acquisition of FCZ resistance.

AIDS-Related Opportunistic Infections↗
PubMed1993

Serotyping of Cryptococcus neoformans by using a monoclonal antibody specific for capsular polysaccharide.

The importance of epidemiological studies of cryptococcosis has increased since the beginning of the AIDS epidemic. Cryptococcus neoformans exists in two varieties defining four serotypes, Cryptococcus neoformans var. neoformans (serotypes A and D) and Cryptococcus neoformans var. gattii (serotypes B and C). The varieties are easy to distinguish by their differences of growth on diagnostic media. We propose here an easy serotyping method combining diagnostic media and a direct immunofluorescence assay with one monoclonal antibody (E1) specific for cryptococcal polysaccharide. The method was validated by the blinded testing of four to five reference strains of each serotype. Immunofluorescence patterns were characteristic of a given serotype provided that the variety of the strain had been defined before. For C. neoformans var. neoformans, a bright, homogeneous staining with several cell aggregates was characteristics of serotype A, whereas only a few serotype D cells were positive. For C. neoformans var. gattii, a completely negative isolate was serotype C, whereas the population of serotype B included a majority of negative cells but also included positive cells with a speckled pattern. The method was then used to serotype 156 clinical isolates from France and isolates from areas where C. neoformans var. gattii was endemic before the AIDS epidemic (13 strains from Rwanda and Zaire and 5 strains from Australia). The specificity of E1 was defined by its reactivity with various Cryptococcus spp. and analyzed according to the described cryptococcal antigenic factors. We conclude from this study that E1 provides a rapid and reliable means to serotype multiple isolates of C. neoformans.

AIDS-Related Opportunistic Infections↗
PubMed1992

[Lung abscess caused by Rhodococcus (Corynebacterium) equi in HIV infection. Two cases].

Rhodococcus (Corynebacterium) equi is a well-known Gram positive bacillus which is usually pathogenic in farm animals but rarely causes diseases in humans. Only 30 cases of human infection have been reported in the literature. R. equi has recently been added to the list of opportunistic agents in severe HIV infection. Its most common manifestation in immunocompromised is a slowly progressive pneumonia which may cavitate. R. equi pulmonary infections are difficult to treat: they usually require prolonged parenteral antibiotic therapy and often need surgical treatment. Two cases of cavitary pneumonia in patients with severe HIV infection are reported here. In one case the disease was associated with pulmonary Kaposi sarcoma and pneumocystis pneumonia; the other case was the first opportunistic infection in the course of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A novel gene constitutively expressed in human lymphoid cells is inducible with interferon-gamma in myeloid cells.

A cluster of at least six interferon-gamma (IFN gamma)-inducible genes designated Ifi201-204 and located on mouse chromosome 1 has recently been described. Here, we report a human IFN-gamma-inducible gene, IFI 16, which has nucleotide sequence similarity with portions of two of the mouse genes, Ifi202 and Ifi204. A full-length cDNA clone derived from IFI 16 [2.709 kilobases (kb)] contained a single open reading frame of 2.187 kb which encoded a putative polypeptide of 729 amino acids and a predicted non-glycosylated M(r) of 80020. IFI 16 mRNA was found to be constitutively expressed in lymphoid cells and in cell lines of both the T and B lineages. By contrast, the mRNA was not expressed by the cell lines HL-60, U937, and K562, which represent early stages of myeloid development, but was strongly inducible in HL-60 and U937 with IFN-gamma. The IFI 16 protein demonstrated a putative domain structure with patchy similarity to the proteins expressed from genes Ifi202 and Ifi204. The mouse and human proteins each contain two analogous approximately 200 amino acid domains which are imperfect copies, but IFI 16 demonstrated additional unique regions, including a Lys-rich N-terminal portion and a "spacer" region between the reiterated domains, analogous to spacer regions in the CD5 and CD8 alpha molecules. Using a panel of inter-species somatic cell hybrid cell lines, IFI 16 was localized to the chromosomal region 1q12----1qter, a region syntenic between mouse and man. DNA blotting indicated that, in contrast to the mouse, IFI 16 is present as a single copy gene in the human genome.

Amino Acid Sequence↗
PubMed1992

Genomic organization and chromosomal location of the human gene encoding the B-lymphocyte activation antigen B7.

The human B lymphocyte activation antigen B7 provides regulatory signals for T lymphocytes as a consequence of binding to its ligands CD28 and CTLA-4. The cDNA for B7 has previously been isolated and predicted to encode a type I membrane protein. The predicted polypeptide has a secretory signal peptide followed by two contiguous Ig-like domains, a hydrophobic transmembrane region and a short cytoplasmic tail. Here we report the exon-intron genomic organization of human B7 and the chromosomal location. The gene has six exons that span approximately 32 kilobases of DNA. Exon 1 is not translated and the second exon contains the initiation ATG codon and encodes a predicted signal peptide. This gene structure is characteristic for several eukaryotic genes with tissue-specific expression. The third and fourth exons correspond to two Ig-like domains whereas the fifth and sixth exons encode respectively the trans-membrane portion and the cytoplasmic tail. This close relationship between exons and functional domains is a characteristic feature of genes of the Ig superfamily. Cell surface expression of the B7 gene product has previously been mapped to human chromosome 12 by antibody reactivity with the B7-specific monoclonal antibody BB-1. We here demonstrate that the B7 gene is located to the q21-qter region of chromosome 3 by DNA blot analysis of human x rodent somatic cell hybrids.

Amino Acid Sequence↗